Work out ballast quantity for track instantly with clear inputs, formula shown and shareable results.
Ballast volume is length times cross-sectional area (width times depth under the sleeper), and mass follows from bulk density, typically 1.5-1.6 t/m3 for crushed granite. Depth under the sleeper is the governing dimension: it spreads axle load onto the formation and provides drainage.
Ballast quantity
volume = length x width x depth; tonnes = volume x bulk density
Rail results are planning estimates only. Verify against the infrastructure manager's rule book, approved braking curves and applicable railway safety regulations.
Usually 250-350 mm under the sleeper on main lines, more where the subgrade is weak or axle loads and speeds are high.
Ballast is angular stone with large voids. The rock itself is about 2.65 t/m3 but the loose bulk figure is around 1.5-1.6 t/m3.